WASHINGTON – The United States faces a "persistent and evolving terrorist threat" within America's borders in the next three years, reads the latestNational Intelligence Estimatereleased Tuesday.

The document, a product of three years of work among the nation's 16 intelligence agencies, says Islamic terrorist groups, especiallyUsama bin Laden's Al Qaeda terror network as well as Iranian-backed Hezbollah and even some smaller non-Muslim groups, are driven by a desire to attack the United States and continue to adapt and improve their capabilities.

The intelligence assessment says increased counterterrorism efforts worldwide over the past five years have curtailed Al Qaeda's ability to attack the United States, but have increased the terror group's desire to hit the homeland.

The focus of terrorist groups remains on high-impact, high-casualty attacks in the U.S. rather than smaller actions, which the NIE suggests means the terror groups are biding their time.

"We should be clear that despite a resurgentAl Qaedathreat and some of their capabilities, they are weaker today than they would have been if we had not taken strong action against them over the last five and a half years," said White House Homeland Security AdviserFrances Fragos Townsend.

Speaking at a conference on open source intelligence, National Security AdviserMike McConnelladded point-blank: Is Al Qaeda as capable as in 2001? No.

But U.S. officials say it's imperative for the country's agencies to learn to be as adaptive as the terrorists.

The United States' intelligence community continues to work on defending the homeland "while anticipating and preparing for future attacks. Our efforts develop as the trends and threats develop and we will continue to fight this way as long as we are threatened by an enemy that seeks to do us harm," Townsend said.

The report states that Al Qaeda is gearing up its operations in tribal areas of Pakistan, including expanding its lieutenants and senior leaders.

"The group is proficient with conventional small arms and improvised explosive devices and is innovative in creating new capabilities and overcoming security obstacles," the report reads.

U.S. officials have warned publicly that a deal between the Pakistani government and tribal leaders allowed Al Qaeda to plot and train more freely in parts of western Pakistan for the last 10 months.

Few operatives have been found in the United States since Sept. 11, 2001, but terror cells are trying to gain a foothold in other small countries that are unstable or don't have the capacity to prevent their intrusion.

Townsend repeated concerns listed in the report that says as the memories of Sept. 11 weaken, international cooperation will wane. That has not happened yet, she said, and the challenge for the United States has so far been less severe than in Western Europe.

"I am not in the near term concerned about the waning of international cooperation. It's actually as strong as it's ever been," Townsend said, adding that Pakistan President Pervez Musharraf has pledged to prevent enabling his country to become a safe haven despite being the target of assassination attempts and a breakdown of a truce between tribal leaders and the government.

The NIE says Al Qaeda continues to seek cooperative agreements with other terror groups and to acquire chemical, biological, nuclear and radiological weapons and "would not hesitate to use them."

Other conclusions reached by the spy agency say: the Lebanese-based Hezbollah terror group may be more likely to consider attacking the United States if it believes the U.S. is directly threatening the group or its main sponsor, Iran. Non-Muslim terrorist groups probably will attack here in the next several years, although on a smaller scale. The judgments don't name any specific groups, but the FBI often warns of violent environmental groups, such as Earth Liberation Front, and others.

Portions of the document, which was approved June 21, were declassified for public release, and several of the findings were discussed last week in House hearings with intelligence officials.

The White House brushed off critics who allege the administration released the intelligence estimate at the same time the Senate is debating Iraq. White House press secretary Tony Snow said Wednesday that the U.S. could not have fought a global war against Al Qaeda before the coalition entered Iraq, and claims that Iraq is in a civil war are "a lot less persuasive" than a few months ago.

"What you see in Iraq is precisely the sort of thing that ought to give confidence in efforts in there. Let me make the point again that you have seen a province, Anbar, which last November was written off as gone. ... In point of fact, Anbar has completely flipped in a period of months because what has happened is the determined application of force, the knowledge on the part of the locals that they can rely on that force and support and the turning of the local population against Al Qaeda," Snow said.

While the report does not contain any shocking or surprising new information, Republican lawmakers on Capitol Hill said the nation cannot let down its guard.

"It says that we need to be even more vigilant, more aware that we are subject to attack here," said Sen. Kay Bailey Hutchison, R-Texas.

But in the last week, reports on this document and another threat assessment on Al Qaeda's resurgence have renewed the debate in Washington about whether the Bush administration is on the right course in its war on terror, particularly in Iraq.

Critics like House Armed Services Committee Chairman Ike Skelton, says the NIE's findings prove that the United States has been sidetracked by Iraq.

"In hindsight, we should have concentrated our efforts on Al Qaeda in Afghanistan from the beginning. We missed an important opportunity when Bin Laden escaped from Tora Bora.

"Now, four years later, we find ourselves facing a resurgent Al Qaeda while our forces are tied down in Iraq. ... As the House voted last week, we must responsibly redeploy our troops out of Iraq, handing responsibility for security over to the Iraqis and leaving only those forces required for limited missions. This will allow us to concentrate our efforts on Afghanistan and the Al Qaeda terrorists who attacked us on 9/11," Skelton, D-Mo., said in a written statement.

Responding to that criticism, Townsend said the War on Terror and operation in Iraq are not separate conflicts.

These are clearly a single conflict by a single determined enemy who is looking for a safe haven. And if they don't have safe haven in Afghanistan, they look for safe haven someplace else. They'd like to find it — and bin Laden's been quite clear — they'd like to find it in Iraq," she said.